The invention relates to a prechamber system and an internal combustion engine with such a prechamber system.
In internal combustion engines (combustion engines), above a particular capacity, the energy of an ignition spark is no longer sufficient to reliably ignite the combustion gas/air mixture—which for emissions reasons is often very lean—in the main combustion chamber. To increase the ignition energy, in a prechamber which is connected with the main combustion chamber via channels, a small part of the mixture is enriched with a small quantity of combustion gas or an additional fuel and ignited. Combustion propagates in the form of ignition flares via the overflow channels out of the prechamber into the main combustion chamber and there ignites the lean mixture.
DE 10 2008 015 744 A1 describes, for example, an ignition device with prechamber into which opens a combustion gas nozzle (gas valve) which is connected to a high-pressure combustion gas line in order to introduce combustion gas into the prechamber under high pressure. Here, the combustion gas is mixed with a leaner (super-stoichiometric) combustion gas/air mixture present in the prechamber and enriches it. An ignition device protrudes into the prechamber to ignite the enriched combustion gas/air mixture and thus finally to ensure ignition of the combustion gas/air mixture present in the main combustion chamber.
In these so-called gas-flushed prechambers, a specific gas quantity is metered into the prechamber during the intake and/or compression stroke via a valve. At around the same time, a super-stoichiometric (λ>1) gas-air mixture is supplied to the main combustion chamber via the inlet valve. An engine operated on the “flushed prechamber” principle is described for example in DE 10 2004 016 260 B4 (Caterpillar).
On the compression stroke, lean mixture flows from the main combustion chamber into the prechamber and there mixes with the rich mixture already present. The aim is to achieve a stoichiometric composition (λ˜1) for an ignitable mixture with high ignition energy.
U.S. Pat. No. 6,129,059 A (HONDA MOTOR CO. LTD.) describes an internal combustion engine and the arrangement of channels between the main combustion chamber and the prechamber.
U.S. Pat. No. 4,170,968 A (TOYOTA MOTOR CO. LTD.) describes in more detail the arrangement of the overflow channels in the prechamber and the position of the spark plugs in relation to these channels.
DE 10 2004 016 260 (CATERPILLAR MOTOREN GMBH) discloses a gas engine with a prechamber into which gas flows via a channel. The cylinder head of a gas engine shown has a flushed prechamber and a separate gas supply channel to supply a combustion chamber with gas for the ignition energy, wherein the ordinary ignition process takes place via a spark plug. A magnetic valve is arranged in a receiver region in the gas supply channel, and the outlet opens directly into the combustion chamber.